The present invention relates to an apparatus for freeing the bottom wraps and the downwinds of yarn from a textile bobbin to provide a free yarn end in preparation for subsequent unwinding of the bobbin. An apparatus of the general type to which the present invention is directed is disclosed in West German patent document No. DE-AS 15 60 571.
In textile manufacturing yarn is produced and wound onto bobbins and is then transferred onto packages by automatic winders. The last windings of the yarn on the bobbins are in the form of downwinds that spiral from the top of the bobbin down around the body of the yarn and then wound as bottom wraps around the bottom of the bobbin. In some cases only downwinds are formed without bottom wraps.
In preparing bobbins for processing by automatic winders, it is necessary to free predetermined lengths of yarn from the bobbin and preferably position the free ends at a preferred location along the length of the bobbins so that the yarn ends can readily be engaged by the automatic winder. This yarn freeing operation is normally performed by rotating the bobbin and applying pneumatic or mechanical means for acting on the underwindings and bottom wraps of yarn to free the yarn ends and unwind the yarn from the bobbin to a location convenient for subsequent engagement by the automatic winder.
In prior art devices of this type the bottoms of the bobbins are supported on and slide along supports as they are transported to, supported during and transported away from the yarn end freeing operation. Such bottom supports interfere with desired yarn end freeing operation by obstructing free downward pneumatic or mechanical action beyond the bottom ends of the bobbins, but desired elimination of the supports has not been possible because the bobbins must be supported. In this regard, attempts have been made to reduce the undesirable effect of the supports by special shaping, but such attempts have not been successful to the extent desired. It is to this problem that the present invention is directed.